staging: lustre: ptlrpc: list_for_each improvements.
authorNeilBrown <neilb@suse.com>
Tue, 20 Feb 2018 02:23:38 +0000 (13:23 +1100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 22 Feb 2018 14:06:36 +0000 (15:06 +0100)
1/ use list_for_each_entry_safe() instead of
   list_for_each_safe() and similar.

2/ use list_first_entry() and list_last_entry() where appropriate.

3/ When removing everything from a list, use
     while ((x = list_first_entry_or_null()) {
   as it makes the intent clear

4/ No need to take a spinlock in a structure that is about
   to be freed - we must have exclusive access at this stage.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/ptlrpc/client.c
drivers/staging/lustre/lustre/ptlrpc/import.c
drivers/staging/lustre/lustre/ptlrpc/pinger.c
drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c
drivers/staging/lustre/lustre/ptlrpc/recover.c
drivers/staging/lustre/lustre/ptlrpc/service.c

index d4c641d..ca096fa 100644 (file)
@@ -504,19 +504,16 @@ void ptlrpc_request_cache_free(struct ptlrpc_request *req)
  */
 void ptlrpc_free_rq_pool(struct ptlrpc_request_pool *pool)
 {
-       struct list_head *l, *tmp;
        struct ptlrpc_request *req;
 
-       spin_lock(&pool->prp_lock);
-       list_for_each_safe(l, tmp, &pool->prp_req_list) {
-               req = list_entry(l, struct ptlrpc_request, rq_list);
+       while ((req = list_first_entry_or_null(&pool->prp_req_list,
+                                              struct ptlrpc_request, rq_list))) {
                list_del(&req->rq_list);
                LASSERT(req->rq_reqbuf);
                LASSERT(req->rq_reqbuf_len == pool->prp_rq_size);
                kvfree(req->rq_reqbuf);
                ptlrpc_request_cache_free(req);
        }
-       spin_unlock(&pool->prp_lock);
        kfree(pool);
 }
 EXPORT_SYMBOL(ptlrpc_free_rq_pool);
@@ -656,16 +653,13 @@ static void __ptlrpc_free_req_to_pool(struct ptlrpc_request *request)
 void ptlrpc_add_unreplied(struct ptlrpc_request *req)
 {
        struct obd_import       *imp = req->rq_import;
-       struct list_head        *tmp;
        struct ptlrpc_request   *iter;
 
        assert_spin_locked(&imp->imp_lock);
        LASSERT(list_empty(&req->rq_unreplied_list));
 
        /* unreplied list is sorted by xid in ascending order */
-       list_for_each_prev(tmp, &imp->imp_unreplied_list) {
-               iter = list_entry(tmp, struct ptlrpc_request,
-                                 rq_unreplied_list);
+       list_for_each_entry_reverse(iter, &imp->imp_unreplied_list, rq_unreplied_list) {
 
                LASSERT(req->rq_xid != iter->rq_xid);
                if (req->rq_xid < iter->rq_xid)
@@ -1001,18 +995,14 @@ struct ptlrpc_request_set *ptlrpc_prep_fcset(int max, set_producer_func func,
  */
 void ptlrpc_set_destroy(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp;
-       struct list_head *next;
+       struct ptlrpc_request *req;
        int expected_phase;
        int n = 0;
 
        /* Requests on the set should either all be completed, or all be new */
        expected_phase = (atomic_read(&set->set_remaining) == 0) ?
                         RQ_PHASE_COMPLETE : RQ_PHASE_NEW;
-       list_for_each(tmp, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_set_chain);
-
+       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
                LASSERT(req->rq_phase == expected_phase);
                n++;
        }
@@ -1021,9 +1011,9 @@ void ptlrpc_set_destroy(struct ptlrpc_request_set *set)
                 atomic_read(&set->set_remaining) == n, "%d / %d\n",
                 atomic_read(&set->set_remaining), n);
 
-       list_for_each_safe(tmp, next, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_set_chain);
+       while ((req = list_first_entry_or_null(&set->set_requests,
+                                              struct ptlrpc_request,
+                                              rq_set_chain))) {
                list_del_init(&req->rq_set_chain);
 
                LASSERT(req->rq_phase == expected_phase);
@@ -1640,7 +1630,7 @@ static inline int ptlrpc_set_producer(struct ptlrpc_request_set *set)
  */
 int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp, *next;
+       struct ptlrpc_request *req, *next;
        struct list_head comp_reqs;
        int force_timer_recalc = 0;
 
@@ -1648,9 +1638,7 @@ int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set)
                return 1;
 
        INIT_LIST_HEAD(&comp_reqs);
-       list_for_each_safe(tmp, next, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_set_chain);
+       list_for_each_entry_safe(req, next, &set->set_requests, rq_set_chain) {
                struct obd_import *imp = req->rq_import;
                int unregistered = 0;
                int rc = 0;
@@ -2126,13 +2114,11 @@ int ptlrpc_expire_one_request(struct ptlrpc_request *req, int async_unlink)
  */
 void ptlrpc_expired_set(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp;
+       struct ptlrpc_request *req;
        time64_t now = ktime_get_real_seconds();
 
        /* A timeout expired. See which reqs it applies to...  */
-       list_for_each(tmp, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_set_chain);
+       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
 
                /* don't expire request waiting for context */
                if (req->rq_wait_ctx)
@@ -2173,13 +2159,10 @@ EXPORT_SYMBOL(ptlrpc_mark_interrupted);
  */
 static void ptlrpc_interrupted_set(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp;
-
+       struct ptlrpc_request *req;
        CDEBUG(D_RPCTRACE, "INTERRUPTED SET %p\n", set);
 
-       list_for_each(tmp, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_set_chain);
+       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
 
                if (req->rq_phase != RQ_PHASE_RPC &&
                    req->rq_phase != RQ_PHASE_UNREG_RPC)
@@ -2194,14 +2177,12 @@ static void ptlrpc_interrupted_set(struct ptlrpc_request_set *set)
  */
 int ptlrpc_set_next_timeout(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp;
        time64_t now = ktime_get_real_seconds();
        int timeout = 0;
        struct ptlrpc_request *req;
        time64_t deadline;
 
-       list_for_each(tmp, &set->set_requests) {
-               req = list_entry(tmp, struct ptlrpc_request, rq_set_chain);
+       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
 
                /* Request in-flight? */
                if (!(((req->rq_phase == RQ_PHASE_RPC) && !req->rq_waiting) ||
@@ -2240,16 +2221,13 @@ int ptlrpc_set_next_timeout(struct ptlrpc_request_set *set)
  */
 int ptlrpc_set_wait(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp;
        struct ptlrpc_request *req;
        int rc, timeout;
 
        if (set->set_producer)
                (void)ptlrpc_set_producer(set);
        else
-               list_for_each(tmp, &set->set_requests) {
-                       req = list_entry(tmp, struct ptlrpc_request,
-                                        rq_set_chain);
+               list_for_each_entry(req, &set->set_requests, rq_set_chain) {
                        if (req->rq_phase == RQ_PHASE_NEW)
                                (void)ptlrpc_send_new_req(req);
                }
@@ -2322,9 +2300,7 @@ int ptlrpc_set_wait(struct ptlrpc_request_set *set)
                 * the error cases -eeb.
                 */
                if (rc == 0 && atomic_read(&set->set_remaining) == 0) {
-                       list_for_each(tmp, &set->set_requests) {
-                               req = list_entry(tmp, struct ptlrpc_request,
-                                                rq_set_chain);
+                       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
                                spin_lock(&req->rq_lock);
                                req->rq_invalid_rqset = 1;
                                spin_unlock(&req->rq_lock);
@@ -2335,9 +2311,7 @@ int ptlrpc_set_wait(struct ptlrpc_request_set *set)
        LASSERT(atomic_read(&set->set_remaining) == 0);
 
        rc = set->set_rc; /* rq_status of already freed requests if any */
-       list_for_each(tmp, &set->set_requests) {
-               req = list_entry(tmp, struct ptlrpc_request, rq_set_chain);
-
+       list_for_each_entry(req, &set->set_requests, rq_set_chain) {
                LASSERT(req->rq_phase == RQ_PHASE_COMPLETE);
                if (req->rq_status != 0)
                        rc = req->rq_status;
@@ -2716,8 +2690,7 @@ EXPORT_SYMBOL(ptlrpc_request_addref);
 void ptlrpc_retain_replayable_request(struct ptlrpc_request *req,
                                      struct obd_import *imp)
 {
-       struct list_head *tmp;
-
+       struct ptlrpc_request *iter;
        assert_spin_locked(&imp->imp_lock);
 
        if (req->rq_transno == 0) {
@@ -2744,10 +2717,7 @@ void ptlrpc_retain_replayable_request(struct ptlrpc_request *req,
        LASSERT(imp->imp_replayable);
        /* Balanced in ptlrpc_free_committed, usually. */
        ptlrpc_request_addref(req);
-       list_for_each_prev(tmp, &imp->imp_replay_list) {
-               struct ptlrpc_request *iter =
-                       list_entry(tmp, struct ptlrpc_request, rq_replay_list);
-
+       list_for_each_entry_reverse(iter, &imp->imp_replay_list, rq_replay_list) {
                /*
                 * We may have duplicate transnos if we create and then
                 * open a file, or for closes retained if to match creating
@@ -2955,7 +2925,7 @@ int ptlrpc_replay_req(struct ptlrpc_request *req)
  */
 void ptlrpc_abort_inflight(struct obd_import *imp)
 {
-       struct list_head *tmp, *n;
+       struct ptlrpc_request *req, *n;
 
        /*
         * Make sure that no new requests get processed for this import.
@@ -2969,10 +2939,7 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
         * locked?  Also, how do we know if the requests on the list are
         * being freed at this time?
         */
-       list_for_each_safe(tmp, n, &imp->imp_sending_list) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_list);
-
+       list_for_each_entry_safe(req, n, &imp->imp_sending_list, rq_list) {
                DEBUG_REQ(D_RPCTRACE, req, "inflight");
 
                spin_lock(&req->rq_lock);
@@ -2984,10 +2951,7 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
                spin_unlock(&req->rq_lock);
        }
 
-       list_for_each_safe(tmp, n, &imp->imp_delayed_list) {
-               struct ptlrpc_request *req =
-                       list_entry(tmp, struct ptlrpc_request, rq_list);
-
+       list_for_each_entry_safe(req, n, &imp->imp_delayed_list, rq_list) {
                DEBUG_REQ(D_RPCTRACE, req, "aborting waiting req");
 
                spin_lock(&req->rq_lock);
@@ -3014,12 +2978,9 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
  */
 void ptlrpc_abort_set(struct ptlrpc_request_set *set)
 {
-       struct list_head *tmp, *pos;
-
-       list_for_each_safe(pos, tmp, &set->set_requests) {
-               struct ptlrpc_request *req =
-                       list_entry(pos, struct ptlrpc_request, rq_set_chain);
+       struct ptlrpc_request *req, *tmp;
 
+       list_for_each_entry_safe(req, tmp, &set->set_requests, rq_set_chain) {
                spin_lock(&req->rq_lock);
                if (req->rq_phase != RQ_PHASE_RPC) {
                        spin_unlock(&req->rq_lock);
index faf0f60..a2c4fc3 100644 (file)
@@ -242,15 +242,13 @@ ptlrpc_inflight_deadline(struct ptlrpc_request *req, time64_t now)
 static unsigned int ptlrpc_inflight_timeout(struct obd_import *imp)
 {
        time64_t now = ktime_get_real_seconds();
-       struct list_head *tmp, *n;
-       struct ptlrpc_request *req;
+       struct ptlrpc_request *req, *n;
        unsigned int timeout = 0;
 
        spin_lock(&imp->imp_lock);
-       list_for_each_safe(tmp, n, &imp->imp_sending_list) {
-               req = list_entry(tmp, struct ptlrpc_request, rq_list);
+       list_for_each_entry_safe(req, n, &imp->imp_sending_list, rq_list)
                timeout = max(ptlrpc_inflight_deadline(req, now), timeout);
-       }
+
        spin_unlock(&imp->imp_lock);
        return timeout;
 }
@@ -263,8 +261,7 @@ static unsigned int ptlrpc_inflight_timeout(struct obd_import *imp)
  */
 void ptlrpc_invalidate_import(struct obd_import *imp)
 {
-       struct list_head *tmp, *n;
-       struct ptlrpc_request *req;
+       struct ptlrpc_request *req, *n;
        unsigned int timeout;
        int rc;
 
@@ -336,19 +333,13 @@ void ptlrpc_invalidate_import(struct obd_import *imp)
                                 */
                                rc = 0;
                        } else {
-                               list_for_each_safe(tmp, n,
-                                                  &imp->imp_sending_list) {
-                                       req = list_entry(tmp,
-                                                        struct ptlrpc_request,
-                                                        rq_list);
+                               list_for_each_entry_safe(req, n,
+                                                        &imp->imp_sending_list, rq_list) {
                                        DEBUG_REQ(D_ERROR, req,
                                                  "still on sending list");
                                }
-                               list_for_each_safe(tmp, n,
-                                                  &imp->imp_delayed_list) {
-                                       req = list_entry(tmp,
-                                                        struct ptlrpc_request,
-                                                        rq_list);
+                               list_for_each_entry_safe(req, n,
+                                                        &imp->imp_delayed_list, rq_list) {
                                        DEBUG_REQ(D_ERROR, req,
                                                  "still on delayed list");
                                }
@@ -557,14 +548,13 @@ static int import_select_connection(struct obd_import *imp)
 static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
 {
        struct ptlrpc_request *req;
-       struct list_head *tmp;
 
        /* The requests in committed_list always have smaller transnos than
         * the requests in replay_list
         */
        if (!list_empty(&imp->imp_committed_list)) {
-               tmp = imp->imp_committed_list.next;
-               req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
+               req = list_first_entry(&imp->imp_committed_list,
+                                      struct ptlrpc_request, rq_replay_list);
                *transno = req->rq_transno;
                if (req->rq_transno == 0) {
                        DEBUG_REQ(D_ERROR, req,
@@ -574,8 +564,8 @@ static int ptlrpc_first_transno(struct obd_import *imp, __u64 *transno)
                return 1;
        }
        if (!list_empty(&imp->imp_replay_list)) {
-               tmp = imp->imp_replay_list.next;
-               req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
+               req = list_first_entry(&imp->imp_replay_list,
+                                      struct ptlrpc_request, rq_replay_list);
                *transno = req->rq_transno;
                if (req->rq_transno == 0) {
                        DEBUG_REQ(D_ERROR, req, "zero transno in replay_list");
index 639070f..b5f3cfe 100644 (file)
@@ -230,17 +230,13 @@ static int ptlrpc_pinger_main(void *arg)
                unsigned long this_ping = cfs_time_current();
                long time_to_next_wake;
                struct timeout_item *item;
-               struct list_head *iter;
+               struct obd_import *imp;
 
                mutex_lock(&pinger_mutex);
                list_for_each_entry(item, &timeout_list, ti_chain) {
                        item->ti_cb(item, item->ti_cb_data);
                }
-               list_for_each(iter, &pinger_imports) {
-                       struct obd_import *imp =
-                               list_entry(iter, struct obd_import,
-                                          imp_pinger_chain);
-
+               list_for_each_entry(imp, &pinger_imports, imp_pinger_chain) {
                        ptlrpc_pinger_process_import(imp, this_ping);
                        /* obd_timeout might have changed */
                        if (imp->imp_pingable && imp->imp_next_ping &&
index 6ed7752..c0fa139 100644 (file)
@@ -197,17 +197,14 @@ ptlrpcd_select_pc(struct ptlrpc_request *req)
 static int ptlrpcd_steal_rqset(struct ptlrpc_request_set *des,
                               struct ptlrpc_request_set *src)
 {
-       struct list_head *tmp, *pos;
-       struct ptlrpc_request *req;
+       struct ptlrpc_request *req, *tmp;
        int rc = 0;
 
        spin_lock(&src->set_new_req_lock);
        if (likely(!list_empty(&src->set_new_requests))) {
-               list_for_each_safe(pos, tmp, &src->set_new_requests) {
-                       req = list_entry(pos, struct ptlrpc_request,
-                                        rq_set_chain);
+               list_for_each_entry_safe(req, tmp, &src->set_new_requests, rq_set_chain)
                        req->rq_set = des;
-               }
+
                list_splice_init(&src->set_new_requests, &des->set_requests);
                rc = atomic_read(&src->set_new_count);
                atomic_add(rc, &des->set_remaining);
@@ -273,8 +270,7 @@ static inline void ptlrpc_reqset_get(struct ptlrpc_request_set *set)
  */
 static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc)
 {
-       struct list_head *tmp, *pos;
-       struct ptlrpc_request *req;
+       struct ptlrpc_request *req, *tmp;
        struct ptlrpc_request_set *set = pc->pc_set;
        int rc = 0;
        int rc2;
@@ -320,8 +316,7 @@ static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc)
        /* NB: ptlrpc_check_set has already moved completed request at the
         * head of seq::set_requests
         */
-       list_for_each_safe(pos, tmp, &set->set_requests) {
-               req = list_entry(pos, struct ptlrpc_request, rq_set_chain);
+       list_for_each_entry_safe(req, tmp, &set->set_requests, rq_set_chain) {
                if (req->rq_phase != RQ_PHASE_COMPLETE)
                        break;
 
index 5bb9f9f..2ea0a7f 100644 (file)
@@ -66,8 +66,7 @@ void ptlrpc_initiate_recovery(struct obd_import *imp)
 int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
 {
        int rc = 0;
-       struct list_head *tmp, *pos;
-       struct ptlrpc_request *req = NULL;
+       struct ptlrpc_request *req = NULL, *pos;
        __u64 last_transno;
 
        *inflight = 0;
@@ -86,8 +85,8 @@ int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
 
        /* Replay all the committed open requests on committed_list first */
        if (!list_empty(&imp->imp_committed_list)) {
-               tmp = imp->imp_committed_list.prev;
-               req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);
+               req = list_last_entry(&imp->imp_committed_list,
+                                     struct ptlrpc_request, rq_replay_list);
 
                /* The last request on committed_list hasn't been replayed */
                if (req->rq_transno > last_transno) {
@@ -119,13 +118,13 @@ int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
         * the imp_replay_list
         */
        if (!req) {
-               list_for_each_safe(tmp, pos, &imp->imp_replay_list) {
-                       req = list_entry(tmp, struct ptlrpc_request,
-                                        rq_replay_list);
-
-                       if (req->rq_transno > last_transno)
+               struct ptlrpc_request *tmp;
+               list_for_each_entry_safe(tmp, pos, &imp->imp_replay_list,
+                                        rq_replay_list) {
+                       if (tmp->rq_transno > last_transno) {
+                               req = tmp;
                                break;
-                       req = NULL;
+                       }
                }
        }
 
@@ -211,13 +210,10 @@ int ptlrpc_resend(struct obd_import *imp)
  */
 void ptlrpc_wake_delayed(struct obd_import *imp)
 {
-       struct list_head *tmp, *pos;
-       struct ptlrpc_request *req;
+       struct ptlrpc_request *req, *pos;
 
        spin_lock(&imp->imp_lock);
-       list_for_each_safe(tmp, pos, &imp->imp_delayed_list) {
-               req = list_entry(tmp, struct ptlrpc_request, rq_list);
-
+       list_for_each_entry_safe(req, pos, &imp->imp_delayed_list, rq_list) {
                DEBUG_REQ(D_HA, req, "waking (set %p):", req->rq_set);
                ptlrpc_client_wake_req(req);
        }
index 99aeb29..4941722 100644 (file)
@@ -726,8 +726,6 @@ static void ptlrpc_server_drop_request(struct ptlrpc_request *req)
        struct ptlrpc_service_part *svcpt = rqbd->rqbd_svcpt;
        struct ptlrpc_service *svc = svcpt->scp_service;
        int refcount;
-       struct list_head *tmp;
-       struct list_head *nxt;
 
        if (!atomic_dec_and_test(&req->rq_refcount))
                return;
@@ -776,9 +774,7 @@ static void ptlrpc_server_drop_request(struct ptlrpc_request *req)
                        /* remove rqbd's reqs from svc's req history while
                         * I've got the service lock
                         */
-                       list_for_each(tmp, &rqbd->rqbd_reqs) {
-                               req = list_entry(tmp, struct ptlrpc_request,
-                                                rq_list);
+                       list_for_each_entry(req, &rqbd->rqbd_reqs, rq_list) {
                                /* Track the highest culled req seq */
                                if (req->rq_history_seq >
                                    svcpt->scp_hist_seq_culled) {
@@ -790,10 +786,9 @@ static void ptlrpc_server_drop_request(struct ptlrpc_request *req)
 
                        spin_unlock(&svcpt->scp_lock);
 
-                       list_for_each_safe(tmp, nxt, &rqbd->rqbd_reqs) {
-                               req = list_entry(rqbd->rqbd_reqs.next,
-                                                struct ptlrpc_request,
-                                                rq_list);
+                       while ((req = list_first_entry_or_null(
+                                       &rqbd->rqbd_reqs,
+                                       struct ptlrpc_request, rq_list))) {
                                list_del(&req->rq_list);
                                ptlrpc_server_free_request(req);
                        }